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Biomedical subjects

N Ohta

Publications and source records attributed to N Ohta.

At least 289 records · Page 16Linked to original sources
PubMed1984

Changes in permeability of rabbit articular cartilage caused by joint contracture as revealed by the peroxidase method.

Changes in permeability of adult rabbit articular cartilage caused by joint contracture were studied by light and transmission electron microscopy, employing horseradish peroxidase (HRP) as an indicator. The knee joint was plaster-immobilized for 0, 2, 4, 6, or 8 weeks in the flexion position. One ml of 4% HRP was administered in the articular cavity of the knee joint and allowed to diffuse and permeate into the articular cartilage. Distribution of the permeated HRP was visualized in the cartilage taken from the lateral condyle of the femur, utilizing the DAB-H2O2 reaction. In the normal and the non-immobilized joints, the permeated HRP reached to the matrix and chondrocytes situated in the deep layer of the articular cartilage. HRP was heavily deposited in the intercellular matrices, particularly around the chondrocytes, and was actively endocytosed by these cells. In the plaster-immobilized joints, especially after 4 weeks or longer of immobilization, the administered HRP had not permeated well and was restricted to the surface (lamina splendens) and the superficial layer of the cartilage. These results show that administered HRP diffuses into the deep layer of the articular cartilage and is actively endocytosed by chondrocytes and that the permeability of articular cartilage is remarkably reduced by joint contracture.

Animals↗
PubMed1984

[Renal autotransplantation for ureteral lesions--the indication and the results of operation].

Renal autotransplantation has been a treatment of choice for renovascular hypertension, renal artery aneurysm, complicated staghorn calculi, ureteral disorders and others. The paper reports 5 cases of extensively damaged ureter and discusses the indication and the results of operation. There were three cases of postoperative extensive ureteral stricture. One patient had postoperative ureteral injury with retroperitoneal abscess. The last one showed renal foreign body calculi with recurrent pyelonephritis after ureterocutaneostomy. The postoperative course of four patients had been uneventful revealing well functioning autotransplanted kidneys without hydronephrosis and infection during the follow-up period of 22 to 42 months. However, the patient with the ureteral injury and retroperitoneal abscess died of bleeding from renal vein anastomosis on the 15th postoperative day, since the renal pedicle showed marked inflammatory change including renal vein wall. Subsequently, autotransplantation is contraindicated in the cases with marked inflammation in the renal pedicle. In cases of various other ureteral lesions including long distance ureteral stricture, this procedure is recommended when neither the end to side ureteral anastomosis, Boari's bladder flap operation nor bladder hitch operation is feasible.

Adolescent↗
PubMed1984

[Primary hyperparathyroidism in cases of urinary stone].

During the 5-year period from October, 1978 to September, 1983, primary hyperparathyroidism has been found at our clinic in 16 out of 395 cases of urinary stones (4.1%) and in 12.6% of the recurrent or multiple stone-forming patients. Plasma-ionized calcium level and rapid rapid calcium load test were most valuable in the diagnosis of primary hyperparathyroidism. It has been proved that neck surgery for primary hyperparathyroidism prevents recurrence of urinary tract stones.

Adolescent↗
PubMed1983

Esterase-like activity of human serum albumin II: reaction with N-trans-cinnamoylimidazoles.

To elucidate the details of the esterase activity of human serum albumin, the reaction of N-trans-cinnamoylimidazoles with albumin was investigated kinetically at various pHs at 25 degrees. The reaction consisted of the acylation of albumin (probably the tyrosine-411 residue) by the substrate and the deacylation of cinnamoyl-albumin. The acylation was approximately 10--100-fold faster than the spontaneous hydrolysis of the substrate over the pH range examined. The pH profile for the deacylation rate constant indicated the participation of a group having a pKa of approximately 9.4. The deacylation was subjected to the effect of deuterium oxide. The electron-withdrawing substituent facilitated the deacylation; the Hammett rho value was 1.63. These results suggest that the deacylation proceeded via general base catalysis by this group.

Acylation↗
PubMed1983

Changes in alkaline phosphatase activity in rabbit articular cartilage associated with ageing and joint contracture.

Changes in alkaline phosphatase (ALPase) activity in rabbit articular cartilage induced by joint contracture were studied by light and electron microscopy. The knee joint was plaster-immobilized for 3--9 weeks in the flexion position. Three different age groups of rabbits were examined, at the age of 1 month (young), 1 year (adult), and over 2.5 years (old). ALPase activity was detected in the cartilage taken from the distal end of the femur, employing the lead citrate method. Positive activity was primarily localized in the plasma membrane of the chondrocytes and also in the pericellular matrix vesicles. Before immobilization the positive cells were distributed exclusively in the deep zone of the cartilage, whereas after immobilization activity was present in cells both in the middle and deep zones. This phenomenon was most evident in the old group.

Aging↗
PubMed1983

HLA-DR MT and MB antigens in Takayasu disease.

Recent studies on the pathogenesis of Takayasu disease have focussed on the participation of genetic factors, and HLA analysis has confirmed the close relationship between Takayasu disease and HLA Bw52. In an attempt to investigate the association of immune response gene with the disease, HLA-DR (DR-1, -2, -3, -4, -5, -w6, -7, -w8, -w9, -w10), MT (-1, -2, -3), MB (-1, -3) antigens were studied in 52 patients with Takayasu disease and the data compared with findings in healthy Japanese. As there were no statistical differences between the two groups in the frequencies of all these antigens, genetic factors in Takayasu disease may be much more closely associated with B than with D loci.

Aortic Arch Syndromes↗
PubMed1983

Antigen-specific suppressor T lymphocytes (Leu-2a+3a-) in human schistosomiasis japonica.

Immunoregulatory mechanisms in human schistosomiasis japonica were investigated through in vitro T lymphocyte-macrophage co-culture experiments. High responder T lymphocytes responded to the schistosomal adult worm antigen in the presence of HLA-DR-compatible low responder macrophages, whereas low responder T lymphocytes failed to respond to this antigen even in the presence of HLA-DR-compatible high responder macrophages. This observation strongly suggested that T lymphocytes, but not macrophages, controlled the low responsiveness to the schistosomal adult worm antigen. When high responder lymphocytes were challenged with the schistosomal antigen in the presence of low responder T lymphocytes, low responder T lymphocytes caused an antigen-specific suppression, in a dose-dependent manner, of the responsiveness of high responder lymphocytes. The suppressor T lymphocytes were mitomycin C resistant and were positive for Leu-2a, but were negative for Leu-3a. When Leu-2a+ T lymphocytes were depleted from low responder T lymphocytes, a vigorous response by the Leu-2a-depleted T lymphocytes (Leu-2a-3a+) to the schistosomal adult worm antigen was observed. By adding back the Leu-2a+ T lymphocytes into autologous T lymphocyte subpopulations, the specific response to the adult worm antigen was completely suppressed. These findings clearly demonstrate the existence of Leu-2a+3a- suppressor T lymphocytes that can control low responsiveness to the schistosomal adult worm antigen in man.

Adult↗
PubMed1983

[Effect of Moristerol (anti-cholesterolemic agent) on benign prostatic hypertrophy].

Moristerol was orally administered in 20 cases of benign prostatic hypertrophy. One capsule of Moristerol contained 200 mg of soysterol . In all the cases, 9 capsules of Moristerol were given per day in three divided doses for 6 weeks. Clinical improvement was observed in 11 of the 20 cases (55%). It consisted mainly of subjective complaints such as improvement of dysuria, narrow and weak urinary stream and feeling of incomplete voiding. As objective findings, a statistically significant decrease of residual urine volume was noted after treatment, although shrinkage of the enlarged prostate was not clear upon palpation or roentgenography. In addition to the improvement of symptoms, serum lipid peroxide which might be considered to be a provocative cause of benign prostatic hypertrophy, was also significantly decreased by Moristerol administration. No marked side effects were seen in this study.

Anticholesteremic Agents↗
PubMed1983

[Cefotaxime concentrations in the blood and kidney].

Serum and renal levels of cefotaxime (CTX) were studied. Biological half-life time values in serum of rat following 100 mg/kg intraperitoneal injection were 27.58 minutes by bioassay and 25.02 minutes by high performance liquid chromatography, and that in kidney was 27.79 minutes by bioassay. CTX attained high levels in kidney of both human and rat. The concentration was higher in the cortex than that in the medulla. The activity could not be detected in the fraction of brush border, mitochondria and lysosome. This finding was thought to be a favorable characteristic in conjunction with the gradual decrease in the kidney tissue parallel to serum level.

Adult↗
PubMed1983

[Left ventricular diastolic performance in patients with myocardial infarction: assessment with backward method of radionuclide angiography].

Radionuclide technique in the evaluation of left ventricular (LV) diastolic performance has been applied in patients with myocardial infarction (MI). But the late diastolic LV volume curve obtained from the radionuclide angiogram is unreliable, whenever we sum up radioactivities by ECG-triggered method (conventional method) because of respiratory arrhythmia. The purpose of the present study was (1) to estimate the reliability of diastolic LV volume curve obtained from the radionuclide angiogram by our new method (backward method: backward ECG-gated radionuclide angiogram to the preceding R wave), and (2) to determine the availability of Phase 1 max and Phase 3 max as the indexes of LV diastolic performance. We analyzed LV volume curve and its dV/dt curve in 29 cases by both conventional and backward methods. The LV diastolic period was equally divided into three time intervals. The early, mid and late trisections of the diastolic period were expressed as phase 1, phase 2 and phase 3, respectively. A Phase max was defined as maximum dV/dt in the phase corrected for end-diastolic counts. At first, ejection fraction (EF), Phase 1 max, Phase 2 max and Phase 3 max were compared between the two different methods to estimate the reliability of diastolic LV volume curve obtained from a backward method. The backward method correlated well with the conventional method regarding EF and Phase 1 max (r = 0.965 and r = 0.940, respectively), but there was no correlation regarding Phase 3 max. This indicated that LV diastolic volume curve obtained from the backward method was reliable. In the second place, we analyzed LV dV/dt curve obtained from the backward method in 8 controls and 28 MI patients to determine the availability of Phase max as the indexes of LV diastolic performance. Phase 1 max was reduced earlier than a decrease of EF, and Phase 3 max was increased prior to a decrease of EF in MI. These data indicated that Phase 1 max and Phase 3 max as the indexes of LV diastolic performance were more sensitive than the indexes of LV systolic performance. Also MI patient had an abnormality in early diastolic filling and an increased atrial contraction in late diastolic filling of the left ventricle. The mechanism of abnormal LV early diastolic filling, even in the absence of abnormal systolic function, might be impaired LV suction because of fibrosis or the relatively ischemic myocardium. In mild to moderate LV failure atrial contraction compensated abnormal early diastolic filling, but there was no such a compensation in severe LV failure. It may suggest the limitation of atrial function as a booster pump.

Aged↗